sales management

let me begin by seeing i'm a complete and utter newbie when it comes to programming. I've tried to sink my teeth into more than once, but it hasn't been paid off. That's why i'm turning to you guys for help.

I work at a face to face marketing office. Of course this means we work with salestargets and people are measured by their number of sales. As of now i'm not pleased with the software we've been granted by HQ. It's really a mess. I wanna write my own software for managing the sales of my own employees and the office as a whole. I've got all kinds of wild plans and things i'd like to include but i'm going to start small. Also, I believe this program could be achieved by using Excel, since all it needs to do is compute and numbers and allocate them to employees.

My question is how I can figure this out. The basic structure will be simple. At the top there's the office as a whole of course. I will need three different timescales by weeks, by months and by quarters of years (also a timescale for custom isn't a bad idea). In each timescale there needs to be a representation of put in hours of work, number of sales made and of course number of sales made per hour in that timescale. This information of course is gained by summing up the different information of the salespeople. They'll need also to be measured in the same way as the whole office is measured. Also I'll need a division between salesprojects as we sell different services/stuff. there should also be a different branch of the projects, its hours, its sales and sales per hour. This division needs to be made at the office level but also at the salespeople level. And it needs to stand on its own also.

I hope you get the idea. This is the basic format I want to make. Once I know how i need to make this work, I can more easily orient myself on expanding this and making it better.